[ELF] Add ICF test case to symbol-ordering-file-warnings.s

[jhenderson]

Summary

I noticed that I had missed his particular test case. I think it's simple enough, but others might have some thoughts on what should happen if two identical symbols have been folded, and one or both are in the order file, so hence the review request.

[grimar]

I also don't know. See D43234. Warning seems good idea for me.
Does it make sence to disable ICF for sections involved in ordering ?

[jhenderson]

In D43336#1008776, @grimar wrote:

I also don't know. See D43234. Warning seems good idea for me.
Does it make sence to disable ICF for sections involved in ordering ?

Thanks, I didn't see that review. I'll post my thoughts on it over there.

test/ELF/symbol-ordering-file-warnings.s

 # RUN: ld.lld %t1.o -o %t --symbol-ordering-file %t-order-absolute.txt --unresolved-symbols=ignore-all 2>&1 | \
 # RUN:   FileCheck %s --check-prefixes=WARN,ABSOLUTE
 
 # Check that a warning is emitted for symbols discarded due to --gc-sections.
 # RUN: echo "gc" > %t-order-gc.txt
 # RUN: ld.lld %t1.o -o %t --symbol-ordering-file %t-order-gc.txt --gc-sections --unresolved-symbols=ignore-all 2>&1 | \
 # RUN:   FileCheck %s --check-prefixes=WARN,GC
 
+# Check that a warning is emitted for the symbol removed due to --icf.
+# RUN: echo "icf1" > %t-order-icf.txt
+# RUN: echo "icf2" >> %t-order-icf.txt
+# RUN: ld.lld %t1.o -o %t --symbol-ordering-file %t-order-icf.txt --icf=all --unresolved-symbols=ignore-all 2>&1 | \
+# RUN:   FileCheck %s --check-prefixes=WARN,ICF
+
 # Check that a warning is emitted for symbols discarded due to a linker script /DISCARD/ section.
 # RUN: echo "discard" > %t-order-discard.txt
 # RUN: echo "SECTIONS { /DISCARD/ : { *(.text.discard) } }" > %t.script
 # RUN: ld.lld %t1.o -o %t --symbol-ordering-file %t-order-discard.txt -T %t.script --unresolved-symbols=ignore-all 2>&1 | \
 # RUN:   FileCheck %s --check-prefixes=WARN,DISCARD
 
 # Check that LLD does not warn for discarded COMDAT symbols, if they are present in the kept instance.
 # RUN: echo "comdat" > %t-order-comdat.txt

 # GC:          warning: {{.*}}1.o: unable to order discarded symbol: gc
 # WARN-NOT:    warning:
 # SHARED:      warning: {{.*}}1.o: unable to order shared symbol: shared
 # WARN-NOT:    warning:
 # UNDEFINED:   warning: {{.*}}3.o: unable to order undefined symbol: undefined
 # WARN-NOT:    warning:
 # MISSING:     warning: symbol ordering file: no such symbol: missing
 # MISSING2:    warning: symbol ordering file: no such symbol: missing_sym
+# ICF:         warning: {{.*}}1.o: unable to order discarded symbol: icf2
 # COMDAT:      warning: {{.*}}1.o: unable to order discarded symbol: comdat
 # COMDAT-NEXT: warning: {{.*}}2.o: unable to order discarded symbol: comdat
 # MULTI:       warning: {{.*}}2.o: unable to order absolute symbol: multi
 # MULTI-NEXT:  warning: {{.*}}3.o: unable to order undefined symbol: multi
 # WARN-NOT:    warning:
 
 absolute = 0x1234
 

 comdat:
   nop
 
 .section .text.glob_or_wk,"ax",@progbits
 .weak glob_or_wk
 glob_or_wk:
   nop
 
-.text
+.section .text._start,"ax",@progbits
 .global _start
 _start:
   movq  %rax, absolute
   callq shared
 
+.section .text.icf1,"ax",@progbits
+.global icf1
+icf1:
+    ret
+
+.section .text.icf2,"ax",@progbits
+.global icf2
+icf2:
+    ret
+
 # This is a "good" instance of the symbol
+.section .text.multi,"ax",@progbits
 multi:
   nop